The present invention relates to pressure monitoring devices for externally monitoring the pressure within a disposable pumping cassette used to pump intravenous fluids.
In administering intravenous fluids to patients, it is becoming increasingly common to use inexpensive disposable pumping cassettes made of plastics, which are operated by non disposable driver mechanisms external to the cassette. Such systems have replaced the time honored gravity flow fluid administration systems to a large extent due to their greater accuracy and labor saving features.
Monitoring the pressure of the fluid being discharged from the cassette can provide useful information. As disclosed in U.S. Pat. No. 4,457,753, monitoring discharge pressure permits the detection of occlusions or plugged filters in the cassette outlet line leading to the patient. As disclosed in copending U.S. application Ser. No. 045,958 entitled Disposable Fluid Infusion Pumping Chamber Cassette and Drive Mechanism thereby John Pastrone (the disclosure of which is incorporated herein by reference), monitoring discharge pressure also permits the cassette and its valves to be checked for leakage. Also, the patient's blood pressure can be followed by monitoring discharge line pressure at certain times during the cassette pumping cycle as disclosed in the aforementioned patient application.
However, there should also be a pressure transducer which can detect occlusions in the cassette inlet line from the solution container to the cassette. Furthermore, there is a need for pressure transducers which can make the pressure measurements described above accurately.